Treesearch

Several fixation systems to limit or decrease boron leachability from treated wood have been developed. Some attempts have relied on limiting of water penetration of treated wood using water repellents, monomer and polymer systems. On the other hand, non-toxic polymers such as proteins were tried to reduce amount of boron leached from wood (Thevenon et al. 1997, 1998). Their results showed that protein borates such as albumin and soja protein borates greatly retarded the leaching of boron from treated wood via formation of salt. In addition, precipitation of boron in wood via a calcium...

An Excel spreadsheet developed to solve the ion-exchange equilibrium in wood pulps has been linked by dynamic data exchange to WinGEMS and used to model the non-process elements in the hardwood bleach plant of the Mead/Westvaco Evandale mill. Pulp and filtrate samples were collected from the diffusion washers and final wash press of the bleach plant. A WinGEMS model of the bleach plant was tuned to match the mill data using the sodium and chloride analysis. The spreadsheet was then activated to calculate the bound and free concentrations for H+, Na+, Mg2+, Ca2+, Mn2+, and Ba2+. It adjusted...

Pinyon juniper, Juniperus Monosperma, is a small-diameter and underutilized (SDU) lignocellulosic material. Evaluated were efficacy of base-treated juniper fiber (BTJF) sample for cadmium (Cd 2+ ) sorption and the viability of juniper fiber as a sorbent for the removal of Cd 2+ from water. Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated that carboxylate ion is a major functional group responsible for Cd 2+ sorption and the apparent ideal sodium hydroxide (NaOH) concentration for the base treatment was approximately about 0.5 M. From the batch sorption isotherm test, it...

In an effort to encourage the development of value-added engineered applications for small diameter round timber, research is being conducted at the US Forest Products Laboratory to develop and verify design guidelines for connections with specific application to round timbers. The objective of this work is to provide potential users with a number of viable connection options applicable in the fabrication of engineered, round-wood structural components and systems. Target uses include trusses, built-up flange beams and space frames. This paper presents information on a mortised steel plate...

The reversible, stepwise formation of individual Nb−µ-O−Nb linkages during acid condensation of 2 equiv of A-[alpha]-[SiNb3W9O40]7- (1) to the tri-µ-oxo-bridged structure A-[alpha]-[Si2Nb6W18O77]8- (4) is demonstrated by a combination of X-ray crystallography and variable-pD solution 183W and 29Si NMR spectroscopy. Addition of DCl to a pD 8.4 solution of 1 (Li+ salt in D2O) results in formation of a mono-Nb−µ-O−Nb-linked dimer, A-[alpha]-[Si2Nb6W18O79]12- (2; pD = 3.0−1.3). At pD values between 1.6 and 0.3, two isomers (syn and anti) of the di-µ-oxo-bridged dimer, A-[alpha]-[Si2Nb6W18O78]10...

In a laboratory leaching study, we found that chromated copper arsenate (CCA) treated wood, which had been exposed to one of five soils examined, unexpectedly appeared to gain significant Cr (47%) when measured with an energy-dispersive x-ray fluorescence instrument (American Wood-Preservers' Association (AWPA) Method A9-01 2001). Analysis of some of the leached samples exposed to all five soils by inductively coupled plasma (ICP) spectrometry showed that Fe migrated into the CCA-treated samples from four of the five soils and Mn migrated into wood exposed to two of the five soils. The...

Some engineered wood fiber surfaces are uneven, tend to shift, and have low density. The goal of our research was to develop a playground surface material that cushions impact and is accessible to people with disabilities. In the initial screening phase, we evaluated a variety of in situ surface treatments and mixtures of wood particles combined with various binders. Engineered wood fiber (EWF) was prepared from three species, red maple, ponderosa pine, and one-seed juniper, which have a wide range of densities and bonding properties. In the scale-up phase, we evaluated commercially...

Pulping technologies can be synthesized with fiber loading with simultaneous alkaline peroxide bleaching to produce lightweight high-opacity printing papers. We compared the results of recent experiments on combining oxalic acid pretreated wood chips used for thermomechanical pulp (TMP) with fiber loading and previous experiments on combining similar pulps treated with fungal and microwave pretreatments with fiber loading. For TMP at 100 mL CSF, various species and pretreatments resulted in differences in (a) energy requirements for pulp production, (b) properties of handsheets prepared...

The release of arsenic from wood pressure-treated with chromated copper arsenate (CCA) can be decreased by application of wood finishes, but little is known about the types of finishes that are best suited for this purpose. This study evaluated the effects of finish water repellent content and ultraviolet (UV) radiation on the release of arsenic, copper, and chromium from CCA-treated wood exposed to simulated rainfall. Deck boards treated with CCA were either left unfinished or dipped in a finish prepared with 1%, 3%, or 5% water repellent. All specimens were exposed to leaching from...

To prevent the unintentional transfer of insects and pathogens during world trade, wood products are often heat sterilized. The general requirement is that the center of the wood configuration be held at 133°F (56°C) for 30 min. However, many factors can affect the time required to reach this temperature. This study explored several of these factors, including thickness of boards or cross-sectional dimension of square timbers, wet-bulb depression, and stacking method (solid or stickered). The heating temperature used was 160°F (71°C). Heating time increased with increasing board thickness...